Multi-Channel LiDAR Pulse Timing Compensation for PVT-Invariant Delay
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Solution Overview
Problem
Multi-channel LIDAR systems face challenges in generating high precision, process voltage and time (PVT) invariant pulsed illumination signals due to complex calibration requirements across various temperatures and the need for quick laser turn-off to achieve accurate distance measurements.
Innovation Solution
The implementation of a pulsed signal generator with two digital control circuits within a switching control circuit, including a laser pulse duration digital control circuit and a selection switch activation digital control circuit, which compares pulse widths and adjusts timing to ensure PVT invariance, allowing for precise synchronization of main and selection switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex calibration procedures are implemented to achieve PVT invariance, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The system performs self-calibration by automatically measuring propagation delays in each channel and computing compensation values without requiring external calibration equipment or manual procedures. The calibration is integrated into the normal operation, with the system calibrating itself during runtime to maintain PVT invariance.
Solution Approach 2:
The system continuously monitors temperature, voltage, and time parameters, and uses this feedback to dynamically adjust propagation delay compensation values. The calibration process measures actual delays and feeds this information back to the compensation logic, which then adjusts timing signals to maintain precision across varying conditions.
2Measurement precision
If propagation delay compensation is implemented across multiple channels, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
The compensation system is segmented into independent per-channel measurement and compensation modules. Each channel's propagation delay is measured and compensated independently, allowing the system to handle multiple channels without requiring complex inter-channel coordination. This modular approach scales easily to any number of channels.
Solution Approach 2:
A single compensation methodology is designed to work universally across all channels and various operating conditions (different temperatures, voltages, and channel configurations). The same compensation logic and calibration procedure apply regardless of the number of channels or environmental conditions, simplifying the overall system design.
3Measurement precision
If quick laser turn-off is implemented to improve measurement precision, then measurement precision is improved, but reliability worsens due to potential signal instability
Solution Approach 1:
The system performs preliminary calibration of propagation delays under various operating conditions before actual measurements are taken. By pre-characterizing the system behavior and storing compensation values, the system can quickly switch lasers off for measurements without risking signal instability, as the compensation parameters are already optimized for the current conditions.
Solution Approach 2:
The compensation system is designed to be dynamic, automatically adjusting propagation delay values based on real-time measurements of temperature, voltage, and actual channel behavior. This dynamic adaptation ensures signal stability even during quick laser turn-off cycles, as the system continuously optimizes compensation parameters to match current operating conditions.
Data Source
AI summary
An electronic system and method for generating a pulsed illumination signal in a multi-channel LIDAR application is provided. An example electronic system includes a pulsed signal generator, a pulse emitting circuit, and an illumination source. The pulsed signal generator includes a main switch, a selection switch controlling the flow of current to the illumination source, and a switching control circuit. The switching control circuit configured to receive an illumination source enabled signal indicating a difference between a duration of the illumination source enabled signal and a target duration of the illumination source enabled signal. The switching control circuit is configured to receive the duration target code and determine a main switch enable signal configured to activate the main switch and a selection switch enable signal configured to activate the selection switch, based at least in part on the duration target code and a target overlap.